Pleurobrachia bachei is a small, oval to spherical comb jelly, up to 2 cm high with two long fishing tentacles may stretch 15 cm. It swims with eight longitudinal combs, arranged in four paired rows, that give the comb jellies (ctenophores) their characteristic shimmering appearance. These combs consist of plates of transverse rows of hairs that beat in waves downwards, which produces the shimmering effect. These plates are phosphorescent at night. The gut may bear some colour. Newly hatched specimens are pear-shaped and bear only short rows of combs.
Pleurobrachia bachei is a carnivore, preying on zooplankton, especially copepods.